Voyager Spots Details Of A Whole New World

Voyager 2 has spotted two more moons orbiting Uranus but the dark and distant planet is relinquishing its secrets reluctantly, mission managers said Wednesday.

However, scientists said, the durable little spacecraft is on the threshold of ferreting out torrents of information about the bizarre planet 1.8 billion miles from Earth.

''It's going to be different than anything we've seen before; that's quite clear,'' project scientist Edward Stone said at a news conference at NASA's Jet Propulsion Laboratory in Pasadena, Calif. The conference was monitored by phone in Florida.

Voyager will pass within 50,600 miles of Uranus at 1 p.m. Friday, with its 11 instruments working better than expected. Before the two new moons were detected on photographs taken this week, Voyager had discovered seven other moons.

University of Arizona astronomer Bradford Smith said the cameras also detected a brownish haze enveloping the south polar region and vague cloud movements around the planet. He said the haze might come from chemical reactions triggered by solar radiation.

What's under the 5,000-mile-deep atmosphere of Uranus isn't yet known.

Smith said Uranus and its moons and rings are dark ''and the atmospheric features are extremely low-contrast . . . we have a difficult object to observe. Uranus is not giving up its secrets easily.''

Voyager found brighter targets when it photographed Jupiter in 1979 and Saturn in 1981.

Nevertheless, he said, pictures of a quality equal to the spectacular photos Voyager relayed from Jupiter and Saturn are expected. A camera aboard the spacecraft will take 15- or 16-second time exposures.

The 13th and 14th moons were spotted on each side of the outermost of Uranus' nine known rings. Scientists suspect that each ring is shaped by the gravitational force of two tiny moons.

Smith said scientists cannot yet interpret Voyager's early findings with any certainty because ''we don't even know what we're looking at.''

Stone said it's difficult to provide answers ''to questions that we didn't even know existed 24 hours ago.'' However, he said a bonanza of information is ''just going to come booming out.''

Voyager will penetrate the Uranian system between the outermost of the nine known rings and the innermost of the originally known five moons, Miranda. The craft will pass within 18,000 miles of Miranda.

Voyager was launched from Cape Canaveral Aug. 20, 1977, and will rendezvous with Neptune 2.8 billion miles away on Aug. 25, 1989, before leaving the solar system in the late 1990s.